DOCSLIB.ORG

To View Fulltext

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
To View Fulltext Proc. Indian Acad. Sci. (Chem. Sci.), Vol. 10{L Nos 2 & 3, April 1988, pp. 235-252. Printed in India. Carbon-carbon bond formation and annulation reactions using trimethyl and triethyl orthoformates SUBRATA GHOSH and USHA RANJAN GHATAK* Department of Organic Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Calcutta 7(10 032, India Abstract. Synthetic utility of trimethyl and triethyl orthoformates for carbon-carbon bond formation is briefly surveyed, particularly in relation to dialkoxymethylation, carbonyl transposition-homologation, and cycloalkenone annulation reactions recently reported from the authors' and other laboratories. The complex mechanisms involved in the one-step and two-step annulations of rigid/3, 3'- and 3', &unsaturated ketones have been discussed. Keywords. Trimethyl orthoformate; triethyl orthoformate; cyclopentenone and cyclohex- enone annulations; carbonyl transposition and homologation; bridged bicyelo [3.3.1] nonanes; intramolecular hydride transfer; polycyclic synthesis. 1. Introduction The carbon-oxygen bond formation involving orthoesters, such as trimethyl-or triethyl orthoformate with aldehydes and ketones is a well-established reaction (Fieser and Fieser 1967). On the other hand, carbon-carbon bond formation reactions with orthoesters have not been adequately explored. However, the synthetic potential of these reactions cannot be ignored. Even ring annulation can be achieved in specially designed substrates under proper reaction conditions. In general, carbon-carbon bonds are formed by lhe reaction of orthoesters with compounds having active methylene or methyl groups, diazoketones and diazo esters, and by electrophilic addition and substitution reactions of dialkoxy carbonium ions derived from orthoesters under the influence of Lewis acids (Dewelfe 1970; Perst 1971), with suitable substrates. 2. Reactions of orthoesters with activated methylene or methyl groups Compounds having active methylene groups like acetyl acetone, ethyl acetoacetate and diethylmalonate react with triethyl orthoformate in presence of acetic anhydride to form ethoxymethylene derivatives (Ciaisen 1893), XYCH2 + HC(OEt)3 + 2(CH3CO)20 --> XYC = CH(OEt) + 2CH3CO2H + 2CH3CO2Et (1) X = Y = COCH3; X = COCH3, Y = CO2Et;X = Y = co2gt. * For correspondence 235 236 Subrata Ghosh and Usha Ranjan Ghatak One of the successful applications of this reaction is found in the synthesis of chromone (2) (Sathe et al 1949) by the reaction of the hydroxy ketone (1) with triethyl orthoformate in presence of triethylamine. OH 0 ~]~i 6H5 CH2C6H5HC(OEt) 3 ~ Et3N I 2 More recently, chromones (4) have also been synthesised in high yields in perchloric acid catalysed reactions of o-hydroxy aromatic acyl ketones (3) with triethyl orthoformate (Dorofeenko and Mezheritskii 1968; Dorofeenko and Tkachenko 1972; and Becket et al 1978). 2{~ OH HC{OEI''3 :"R~ R COCHzRI HC'04 RI 0 3 4 The application of the reaction of diazoketones or ethyl diazo-acetate with trialkyl orthocarboxylates in presence of borontrifluoride etherate to form an alkoxyacetal (2) (Schonberg and Praefeke 1964, 1966; Schonberg et al 1966) has remained practically unexplored. RCOCHN2 + RIC(OR2)3 BF3.Et20 ~ RCO-CH(OR 2) -- N2 I CRI(OR2)2 (2) 3. Eiectrophilic substitution with orthoesters 3.1 Reaction of orthoesters with acetylenes. According to Howk and Sauer (1958, 1963), the terminal alkynes react with triethyl orthocarboxylates in presence of Lewis acids such as zinc chloride, zinc iodide, cadmium chloride, magnesium chloride or mercuric bromide to form acetylenic acetals, ketals and orthoesters are illustrated by the preparation of phenyl propargyl aldehyde (5). Znl2 C6HsC~CH + HC(OEt)3 ~ C6HsC-=C - CH(OEt)2 -- C2HsOH ~ H3O+ C6H5. C~C - CHO 5 The carbon-carbon bond-forming step in this reaction probably initiates through an attack by a dialkoxy carbonium ion on the triple bond of the acetylene, and is thus an electrophilic substitution reaction. C-C bond formation and annulation reactions 237 3.2 Aromatic substitution with orthoesters Phenols and aromatic tertiary amines react with triethyl orthoformate in the presence of Lewis acids to form substituted benzaldehyde diethyl acetals through electrophilic attack by the diethoxy carbonium ion on an activated position of the aromatic ring. A number of phenols were converted to substituted o- and p-hydroxy benzaldehydes in 40-96% yields with triethyl orthoformate and aluminium chloride in dichloromethane (Gross et al 1963) e.g. resorcinal (6) produces 2,4-dihydroxy benzaldehyde (8) after hydrolysis of the intermediate H0 0HHooE30:~ H OH , H H AlCl 3 "CH (OEt)2 ~ ~'CHO 6 7 8 diethyl acetal (7). Phenols with electron withdrawing substituents are relatively unreactive or do not react at all. Aryloxy magnesium halides having an unsubstituted ortho position react with triethyl orthoformate to yield, after hydrolysis, o-hydroxy aromatic aldehydes with no detectable amount of the p-hydroxy isomers (Casnati et al 1965). The reaction is sensitive to the electronic and steric properties of substituents on the aromatic ring of the phenol. The specifity observed in this reaction suggests that it involves electrophilic attack on the ortho position of the phenol by the acyl carbon of an orthoformate molecule in an aryloxy magnesium halide-orthoformate complex (9) or by a diethoxy carbonium ion of an ion-pair derived from such a complex. X OMg~ o/Mg~o+ "Y~I/'CH(OEt)2 HC(OEt)$) H~(OEI)2 J > ~.~o gx + C2H50H 9 An application of this type of reaction is found in the conversion of azulene (10) to azulene aldehyde (Treibe 1967; Kirby and Raid 1961; Hafner et al 1961). i_0 Ij 238 Subrata Ghosh and Usha Ranjan Ghatak 4. Addition of orthoesters to double bonds The orthoesters may add to double bonds in the presence of Lewis acids to form 1,1,3-trialkoxy derivatives (3). Probably, a dialkoxy carbonium ion is generated initially which then adds to double bond to form the final product. + RC(OR1)3 + A --~ RC(OR1)2 + RIOA[A=Lewis acid] OR l OR 1 RC(OR1)z+C=C-R-C -C-C ) R-C- CC-OR 1 (3) OR/ ~ I O/R1 f I A variety of olefinic compounds such as ketenes, alkenes, cycloalkenes, enol ethers and enol acetates undergo Lewis-acid-catalysed addition (Perst 1971). 5. Alkylation of enolates with orthoformates Mukaiyama and Hayashi (1974) have shown that silyl enol ether on reaction with trimethyl orthoformate in the presence of TiCI4 produces the /3:ketoacetal (4). OSiR 3 O I HC(OMe)3 ICI R 1 - C = CHR 2 ) R 1 - - CHR 2 - CH(OMe)2. TiCI4 (4) Exploiting this strategy a simple synthesis of 7-ionone (14)has been achieved from 3-methyl cyclohexenone (12), through the /3-keto acetal (13). Me Me Me 1 IMeMgi/Cut 0 2Me3SiCI NEt3 I ~,~OSIMe 3J m~ I C(Oie~j TiCI4 Me Me 0 Me Me OMe Me < OMe Steps v "%~0 ~_4 L3 More recently this group has extende.d (Takazawa and Mukaiyama 1982) this reaction to achieve alkylation on enamines (5). C-C bond formation and annulation reactions 239 R3 R4 0 ~N ~ I. HC(ORS)3 RI--~ --CHR2-'CH(OR5)2 (5) R,CHR2,.~ 1 Lewis ocid > 2 H20 Suzuki et al (1982) have developed a similar route to /3-keto acetals by regiospecific a-dialkoxymethylation of preformed enolates with trialkyl orthofor- mates in presence of Lewis acids, the enolates being generated by addition of methyl lithium to the corresponding silyl enol ethers (6). L< MeLi~ BF3Et20 ~ R" v "OMe (6) R HC(OMe)3- Suzuki et al (1981) have also developed a sequence for the introduction of a dialkoxy alkyl group at the sp 2 hybridised a-position of a,/3-unsaturated ketones as exemplified by the transformation of cyclohexenone (15) to 2-dimethoxymethyl-2- cyclohexen-l-one (16). [~ Me3SiSePh >_ Me3 SiSO3CF3 !_.5 I HC(OMe) OMe OMe ( H202 I ( -o.. / v ~SePh _] 16 An intramolecular ~enolate alkylation with orthoformate (e.g. (17) ~ (18) has been developed by Lombert et al (1986) for cyclopentannulation to enones. OSiMe30Me 0 HOMe I) n-BuLi ~,_ MeO~I/OMe f~OMe OMe ,~OMe 21Cyclohexenone >" ~ Me3SiS03C F'3> L -J SOEPh OMe 3) Me3SiCI,NEt3 ~ i I S02Ph H S02Ph =__7 i_s Recently, Miller (1981) has shown that anthrone (19) on refluxing with 10 molar excess of the orthoester in presence of sulphuric acid resulted in the formation of 10-(diethoxymethyl)-9-anthrone (20) in 65% yield. 240 Subrata Ghosh and Usha Ranjan Ghatak 0 0 19 CH(OEt)2 -- 2_9 A reaction analogous to dialkoxyalkylation of enolates and enamines of ketones has been achieved by Mock and. Tsou (1981) in a single step by reaction of aliphatic and aromatic ketones with diethoxy carbonium fluoroborate (21), generated in situ pO BF4-" ~H(OEt)2( 2l ) ) i- Pr2N Et OEt 2._.22 CH2CI2' - 78"C OEt z_~a JI T-- (OEt)2C" H OCH (OEt)2 ~6CH (OEt) 2 ~ i - Pr2 NEt > -H t ~,'K~,.~H (0 Et) 2 from triethyl orthoformate and boron trifluoride etherate. For example, cyclohex- anone (22) is transformed to the fl-keto acetal (23) by reaction with (21) in the presence of N,N-diisopropylethylamine in methylene chloride at -78~ The regioselectivity observed for unsymmetrically substituted ketones provides a clue to the mechanism for this reaction. The ketone is activated by some form of O-alkylation and is then deprotonated to an enol ether which subsequently yields the observed reaction products by electrophilic addition of diethoxy carbonium ion to the double bond. Based on this one step a-dialkoxyalkylation of ketones, a" simple synthesis of a,fl-unsaturated aldehydes by 1,3-carbonyl transposition through one carbon OMe 0 OMe 0 HC(OEt)3, BF3 El20 > ~CH (OEt):) i-Pr2NEf, CH2CI2 OMe OMe z_55 24 i) NOBH4, MeOH i) 6N HCI OMe I OMe OH OMe OMe J zs C-C bond formation and annulafion reactions 241 homologation has been achieved (table 1) from the authors' laboratory (Dasgupta and Ghatak 1985).
Load more

Recommended publications
  • S41467-018-04983-2.Pdf
    ARTICLE DOI: 10.1038/s41467-018-04983-2 OPEN Novofumigatonin biosynthesis involves a non- heme iron-dependent endoperoxide isomerase for orthoester formation Yudai Matsuda 1,2,3, Tongxuan Bai2, Christopher B.W. Phippen1, Christina S. Nødvig1, Inge Kjærbølling1, Tammi C. Vesth1, Mikael R. Andersen 1, Uffe H. Mortensen 1, Charlotte H. Gotfredsen 4, Ikuro Abe 2 & Thomas O. Larsen 1 1234567890():,; Novofumigatonin (1), isolated from the fungus Aspergillus novofumigatus, is a heavily oxy- genated meroterpenoid containing a unique orthoester moiety. Despite the wide distribution of orthoesters in nature and their biological importance, little is known about the biogenesis of orthoesters. Here we show the elucidation of the biosynthetic pathway of 1 and the identification of key enzymes for the orthoester formation by a series of CRISPR-Cas9-based gene-deletion experiments and in vivo and in vitro reconstitutions of the biosynthesis. The novofumigatonin pathway involves endoperoxy compounds as key precursors for the orthoester synthesis, in which the Fe(II)/α-ketoglutarate-dependent enzyme NvfI performs the endoperoxidation. NvfE, the enzyme catalyzing the orthoester synthesis, is an Fe(II)- dependent, but cosubstrate-free, endoperoxide isomerase, despite the fact that NvfE shares sequence homology with the known Fe(II)/α-ketoglutarate-dependent dioxygenases. NvfE thus belongs to a class of enzymes that gained an isomerase activity by losing the α- ketoglutarate-binding ability. 1 Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, 2800 Kgs. Lyngby, Denmark. 2 Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. 3 Department of Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, China.
    [Show full text]
  • Publikationsliste Internet
    Professor Dr. Alois Fürstner List of Publications 2020 F. Caló, A. Fürstner A Heteroleptic Dirhodium Catalyst for Asymmetric Cyclopropanation with -Stannyl -Diazoacetate. ‘Stereoretentive’ Stille Coupling with Formation of Chiral Quarternary Carbon Centers Angew. Chem. 2020, 132; 14004-14011, Angew. Chem. Int. Ed. 2020, 59, 13900-13907 H. Jin, A. Fürstner Modular Synthesis of Furans with up to Four Different Substituents by a trans‐Carboboration Strategy Angew. Chem. 2020, 132; 13720-13724, Angew. Chem. Int. Ed. 2020, 29, 1316-13622 Z. Meng, A. Fürstner Total Synthesis Provides Strong Evidence: Xestocyclamine A is the Enantiomer of Ingenamine J. Am. Chem. Soc. 2020, 142, 11703-11708 J. Hillenbrand, M. Leutzsch, E. Yiannakas, C. Gordon, C. Wille, N. Nöthling, C. Copéret, A. Fürstner “Canopy Catalysts” for Alkyne Metathesis: Molybdenum Alkylidyne Complexes with a Tripodal Ligand Framework J. Am. Chem. Soc.2020, 142, 11279-11294 M. Heinrich, J. Murphy, M. Ilg, A. Letort, J. Flasz, P. Philipps, A. Fürstner Chagosensine: A Riddle Wrapped in a Mystery Inside an Enigma J. Am. Chem. Soc. 2020, 142, 6409-6422 M. Buchsteiner, L. Martinez-Rodriguez, P. Jerabek, I. Pozo, M. Patzer, N. Nöthling, C. Lehmann, A. Fürstner Catalytic Asymmetric Fluorination of Copper Carbene Complexes: Preparative Advances and a Mechanistic Rationale Chem.–Eur. J. 2020, 26, 2509-2515 2019 S. Peil, A. Fürstner Mechanistic Divergence in the Hydrogenative Synthesis of Furans and Butenolides: Ruthenium Carbenes Formed by gem-Hydrogenation or via Carbophilic Activation of Alkynes Angew. Chem. 2019, 131; 18647-18652; Angew. Chem. Int. Ed. 2019, 58, 18476-18481 L. Huang, Y. Gu, A. Fürstner Iron Catalyzed Reactions of 2-Pyridone Derivatives: 1,6-Addition and Formal Ring Opening/Cross Coupling Chem.
    [Show full text]
  • Aldehydes Can React with Alcohols to Form Hemiacetals
    340 14 . Nucleophilic substitution at C=O with loss of carbonyl oxygen You have, in fact, already met some reactions in which the carbonyl oxygen atom can be lost, but you probably didn’t notice at the time. The equilibrium between an aldehyde or ketone and its hydrate (p. 000) is one such reaction. O HO OH H2O + R1 R2 R1 R2 When the hydrate reverts to starting materials, either of its two oxygen atoms must leave: one OPh came from the water and one from the carbonyl group, so 50% of the time the oxygen atom that belonged to the carbonyl group will be lost. Usually, this is of no consequence, but it can be useful. O For example, in 1968 some chemists studying the reactions that take place inside mass spectrometers needed to label the carbonyl oxygen atom of this ketone with the isotope 18 O. 16 18 By stirring the ‘normal’ O compound with a large excess of isotopically labelled water, H 2 O, for a few hours in the presence of a drop of acid they were able to make the required labelled com- í In Chapter 13 we saw this way of pound. Without the acid catalyst, the exchange is very slow. Acid catalysis speeds the reaction up by making a reaction go faster by raising making the carbonyl group more electrophilic so that equilibrium is reached more quickly. The the energy of the starting material. We 18 also saw that the position of an equilibrium is controlled by mass action— O is in large excess.
    [Show full text]
  • Orthoester Exchange: a Tripodal Tool for Dynamic Covalent and Systems
    Electronic Supplementary Material (ESI) for Chemical Science. This journal is © The Royal Society of Chemistry 2014 Supporting Information Orthoester Exchange: a Tripodal Tool for Dynamic Covalent and Systems Chemistry René-Chris Brachvogel and Max von Delius* Department of Chemistry and Pharmacy, University of Erlangen-Nürnberg, Henkestr. 42, 91054 Erlangen, Germany. * Fax: +49 9131 85 26864; Tel: +49 9131 85 22946; E-mail: [email protected] Contents General experimental section ....................................................................................................................S2 Reversibility of equilibration .....................................................................................................................S7 Investigation of solvents ...........................................................................................................................S11 Investigation of different orthoesters......................................................................................................S13 Investigation of different alcohols ...........................................................................................................S15 Treatment with bicarbonate solution .....................................................................................................S21 Analysis by GC-FID and HPLC-MS ......................................................................................................S23 Manipulation of equilibrium distribution ..............................................................................................S26
    [Show full text]
  • 1 Protecting Group Strategies in Carbohydrate Chemistry
    1 1 Protecting Group Strategies in Carbohydrate Chemistry Anne G. Volbeda, Gijs A. van der Marel, and Jeroen D. C. Codée Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands Carbohydrates are the most densely functionalized class of biopolymers in nature. Every monosaccharide features multiple contiguous stereocenters and bears multiple hydroxyl functionalities. These can, in turn, be decorated with sulfate groups, acyl esters, lactic acid esters and ethers, or phosphate moieties. Amine and carboxylate functions can also be present. Most often, the amine groups are acetylated, but different amide functions are also found, as well as N‐sulfates and alkylated amines. The discrimination of the functional groups on a carbohydrate ring has been and continues to be one of the great challenges in synthetic carbohydrate chemistry [1–3]. This chapter describes the differences in the reactivity of the various func­ tional groups on a carbohydrate ring and how to exploit these in the design of effective protecting group strategies. The protecting groups on a carbohydrate dictate the reactivity of the (mono)saccharide, and this chapter will describe how protecting group effects can be used to control stereoselective transformations (most importantly, glycosylation reactions) and reactivity‐controlled one‐pot synthesis strategies. Applications and strategies in automated synthesis are also highlighted. 1.1 ­Discriminating Different Functionalities on a Carbohydrate Ring The main challenge in the functionalization of a carbohydrate (mono)saccharide is the discrimination of the different hydroxyl functionalities. The – often subtle – differences in reactivity can be capitalized upon to formulate effective protecting group strategies (see Scheme 1.1A).
    [Show full text]
  • Chapter 3. the Concept of Protecting Functional Groups
    Chapter 3. The Concept of Protecting Functional Groups When a chemical reaction is to be carried out selectively at one reactive site in a multifunctional compound, other reactive sites must be temporarily blocked. A protecting group must fulfill a number of requirements: • The protecting group reagent must react selectively (kinetic chemoselectivity) in good yield to give a protected substrate that is stable to the projected reactions. • The protecting group must be selectively removed in good yield by readily available reagents. • The protecting group should not have additional functionality that might provide additional sites of reaction. 3.1 Protecting of NH groups Primary and secondary amines are prone to oxidation, and N-H bonds undergo metallation on exposure to organolithium and Grignard reagents. Moreover, the amino group possesses a lone pair electrons, which can be protonated or reacted with electrophiles. To render the lone pair electrons less reactive, the amine can be converted into an amide via acylation. N-Benzylamine Useful for exposure to organometallic reagents or metal hydrides Hydrogenolysis Benzylamines are not cleaved by Lewis acid Pearlman’s catalyst Amides Basicity of nitrogen is reduced, making them less susceptible to attack by electrophilic reagent The group is stable to pH 1-14, nucleophiles, organometallics (except organolithium reagents), catalytic hydrogenation, and oxidation. Cleaved by strong acid (6N HCl, HBr) or diisobutylaluminum hydride Carbamates Behave like a amides, hence no longer act as nucleophile Stable to oxidizing agents and aqueous bases but may react with reducing agents. Iodotrimethylsilane is often the reagent for removal of this protecting group Stable to both aqueous acid and base Benzoyloxycarbonyl group for peptide synthesis t-butoxycarbonyl group(Boc) is inert to hydrogenolysis and resistant to bases and nucleophilic reagent.
    [Show full text]
  • Studies in Multicyclic Chemistry
    Studies in Multicyclic Chemistry This thesis is submitted in fulfillment of the requirements for the degree of Doctor of Philosophy by Djamal Sholeh Al Djaidi Supervisor Professor Roger Bishop School of Chemistry The University of New South Wales Sydney, Australia December, 2006 PLEASE TYPE THE UNIVERSITY OF NEW SOUTH WALES Thesis/Dissertation Sheet Surname or Family name: AL DJAIDI First name: DJAMAL Other name/s: SHOLEH Abbreviation for degree as given in the University calendar: PhD School: CHEMISTRY Faculty: SCIENCE Title: STUDIES IN MULTICYCLIC CHEMISTRY Abstract 350 words maximum: (PLEASE TYPE) * A series of investigations has been carried out on multicyclic organic systems. The Ritter Reaction was used to obtain bridged imines containing an azacyclohexene functionality. The crystal structure of the benzene inclusion compound of one of these was determined, and also that of another spontaneously oxidised example. The reactivity of these bridged imines was then investigated using mercaptoacetic acid, and also dimethyl acetylenedicarboxylate (DMAD). The three bridged imines studied were found to react with DMAD in totally different ways and produced most unusual products whose structures were proved using X-ray crystallography. Mechanistic explanations are provided for the formation of these novel and totally unexpected products. * 6-Methylidene-3,3,7,7-tetramethylbicyclo[3.3.1]nonan-2-one was reacted with acetonitrile and sulfuric acid to deliberately combine molecular rearrangement with Ritter Reaction chemistry. Five different products were obtained and the pathway of formation of these products was uncovered. The structures of three of these rearranged substances were confirmed by X-ray methods. * The rare tricyclo[5.3.1.1 3,9]dodecane ring system is known to contain severe skeletal distortions due to the nature of its skeleton.
    [Show full text]
  • Long-Chain Polyorthoesters As Degradable Polyethylene Mimics
    This is an open access article published under a Creative Commons Attribution (CC-BY) License, which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited. Article Cite This: Macromolecules 2019, 52, 2411−2420 pubs.acs.org/Macromolecules Long-Chain Polyorthoesters as Degradable Polyethylene Mimics † ‡ † † ‡ Tobias Haider, Oleksandr Shyshov, Oksana Suraeva, Ingo Lieberwirth, Max von Delius, † and Frederik R. Wurm*, † Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany ‡ Institute of Organic Chemistry and Advanced Materials, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany *S Supporting Information ABSTRACT: The persistence of commodity polymers makes the research for degradable alternatives with similar properties necessary. Degradable polyethylene mimics containing orthoester groups were synthesized by olefin metathesis polymerization for the first time. Ring-opening metathesis copolymerization (ROMP) of 1,5-cyclooctadiene with four different cyclic orthoester monomers gave linear copolymers with molecular weights up to 38000 g mol−1. Hydrogenation of such copolymers produced semicrystalline polyethylene- like materials, which were only soluble in hot organic solvents. The crystallinity and melting points of the materials were controlled by the orthoester content of the copolymers. The polymers crystallized similar to polyethylene, but the relatively bulky orthoester groups were expelled from the crystal lattice. The lamellar thickness of the crystals was dependent on the amount of the orthoester groups. In addition, the orthoester substituents influenced the hydrolysis rate of the polymers in solution. Additionally, we were able to prove that non-hydrogenated copolymers with a high orthoester content were biodegraded by microorganisms from activated sludge from a local sewage plant.
    [Show full text]
  • Thesis-1955D-S632n.Pdf (12.10Mb)
    NEW ADDITION REACTIONS OF ETHYLENE OXIDE By FRANK BIER SLEZAK 11 Bachelor of Science Antioch College Yellow Springs, Ohio 1951 Master of Science Oklahoma Agricultural and Mechanical College Stillwater, Oklahoma 1953 Submitted to the faculty of the Graduate School of the Oklahoma Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of DCX::TOR OF HIILOSOPHY May, 1955 i NEW ADDITION REACTIONS OF ETHYLENE OXIDE Thesis Approved: Thesis Adviser eanofthe Graduate School ;; ACKNOWLEDGEMENT The author is deeply grateful to Dr. o.c. Dermer for his continuous guidance during the course of this work. The author also wishes to thank other members of the Chemistry Department for their suggestions and com= roonts on various phases of the research described herein. This work was made possible by the Chemistry Department i n the form of a Graduate Fellowship and by the Cities Service Research and Develop= ment Company, sponsors of part of the worko TABLE OF CONTENTS Page I. INTRODUCTION 1 II. HISTORICAL 2 Preparation of Ethylene Oxide • 2 Physical Pro~rties of Ethylene Oxide 2 Mechanism of Reaction of Ethylene Oxide 2 Reaction of Ethylene Oxide with Co~pounds Containing Active Hydrogen 4 Reaction of Ethylene Oxide with Compounds Containing No Active Hydrogen • 13 III. EXPERIMENTAL PART A. Preparation of Methoxymethyl Acetate and Methylene Diacetate Introduction •• 18 Procedure and Results • 20 Discussion • 0 26 PART B. Acid-Catalyzed Reactions of Ethylene Oxide with Esters and Acetal Analogs Introduction •• • 27 Procedure and Results. 28 Discussion 56 PART C. Reac.tion of Ethylene Oxide with Com­ pounds Capable of Forming Enolates Introduction.
    [Show full text]
  • Orthoester Exchange: a Tripodal Tool for Dynamic Covalent and Systems Chemistry† Cite This: Chem
    Chemical Science View Article Online EDGE ARTICLE View Journal | View Issue Orthoester exchange: a tripodal tool for dynamic covalent and systems chemistry† Cite this: Chem. Sci.,2015,6,1399 Rene-Chris´ Brachvogel and Max von Delius* Reversible covalent reactions have become an important tool in supramolecular chemistry and materials science. Here we introduce the acid-catalyzed exchange of O,O,O-orthoesters to the toolbox of dynamic covalent chemistry. We demonstrate that orthoesters readily exchange with a wide range of alcohols under mild conditions and we disclose the first report of an orthoester metathesis reaction. We Received 14th November 2014 also show that dynamic orthoester systems give rise to pronounced metal template effects, which can Accepted 3rd December 2014 best be understood by agonistic relationships in a three-dimensional network analysis. Due to the DOI: 10.1039/c4sc03528c tripodal architecture of orthoesters, the exchange process described herein could find unique www.rsc.org/chemicalscience applications in dynamic polymers, porous materials and host–guest architectures. Creative Commons Attribution-NonCommercial 3.0 Unported Licence. Introduction tripodal architecture, which we believe will be of benetina range of applications, from molecular sensing19 to three- 5a Dynamic covalent chemistry (DCC)1 has developed into a dimensional framework materials. In contrast to all estab- powerful tool for probing non-covalent interactions,2 identi- lished exchange processes (Scheme 1), the tripodal geometry of fying ligands for medicinally relevant biotargets,3 and for orthoesters also implies that a higher degree of molecular synthesizing interesting molecules,4 porous materials5 and complexity can be generated from a given number of starting polymers.6 Increasingly, dynamic covalent libraries (DCLs) are materials, which is a highly desirable feature in the eld of also investigated from the perspective of the emerging eld of systems chemistry (vide infra).
    [Show full text]
  • Low-Temperature Synthesis of Methylphenidate Hydrochloride
    (19) TZZ ¥¥¥_T (11) EP 2 937 336 A1 (12) EUROPEAN PATENT APPLICATION (43) Date of publication: (51) Int Cl.: 28.10.2015 Bulletin 2015/44 C07D 211/34 (2006.01) (21) Application number: 15164269.1 (22) Date of filing: 16.12.2011 (84) Designated Contracting States: • Kataisto, Erik, Wayne AL AT BE BG CH CY CZ DE DK EE ES FI FR GB West Warwick, RI Rhode Island 02893 (US) GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO • La Lumiere, Knicholaus, Dudley PL PT RO RS SE SI SK SM TR Providence, RI Rhode Island 02908 (US) Designated Extension States: • Reisch, Helge, Alfred BA ME Westerly, RI Rhode Island 02891 (US) (30) Priority: 17.12.2010 US 201061424424 P (74) Representative: Braun, Nils Maiwald Patentanwalts GmbH (62) Document number(s) of the earlier application(s) in Elisenhof accordance with Art. 76 EPC: Elisenstraße 3 11811127.7 / 2 651 892 80335 München (DE) (71) Applicant: Rhodes Technologies Remarks: Coventry, RI 02816 (US) This application was filed on 20-04-2015 as a divisional application to the application mentioned (72) Inventors: under INID code 62. • Huntley, C., Frederick, M. East Greenwich, RI Rhode Island 02818 (US) (54) LOW-TEMPERATURE SYNTHESIS OF METHYLPHENIDATE HYDROCHLORIDE (57) The present invention describes a process for the preparation of methylphenidate hydrochloride. The process involves the esterification of ritalinic acid and methanol in the presence of an acid catalyst at a low temperature. The process may optionally involve the addition of an orthoester. EP 2 937 336 A1 Printed by Jouve, 75001 PARIS (FR) EP 2 937 336 A1 Description BACKGROUND OF THE INVENTION 5 Field of the Invention [0001] The present invention describes a process for the preparation of methylphenidate hydrochloride.
    [Show full text]
  • (12) United States Patent (10) Patent No.: US 6,271,330 B1 Letchford Et Al
    USOO627133OB1 (12) United States Patent (10) Patent No.: US 6,271,330 B1 Letchford et al. (45) Date of Patent: Aug. 7, 2001 (54) FUNCTIONALIZED SILICONE POLYMERS OTHER PUBLICATIONS AND PROCESSES FOR MAKING THE SAME Lai et al., “Synthesis and Characterization of (75) Inventors: Robert James Letchford, Cherryville; C,0)-Bis-(4-hydroxybutyl) Polydimethylsiloxanes,” Jour James Anthony Schwindeman, nal of Polymer Science. Part A. Polymer Chemistry, vol. 33, Lincolnton, both of NC (US); Roderic 1773–1782 (1995). Paul Quirk, Akron, OH (US) Riffle, et al., “Elastomeric Polysiloxane Modifiers for Epoxy Networks,” Epoxy Resin Chemistry II, American Chemical (73) Assignee: FMC Corporation, Philadelphia, PA Society, 1983, pp. 21-54. (US) Wilczek et al., “Preparation and Characterization of Narrow Molecular Mass Distribution Polydimethylsiloxanes, Pol (*) Notice: Subject to any disclaimer, the term of this ish Journal of Chemistry, 55, 2419–2428 (1981). patent is extended or adjusted under 35 McGarth, et al., “An Overview of the Polymerization of U.S.C. 154(b) by 0 days. Cyclosiloxanes.” Initiation of Polymerization, American Chemical Society, 1983, pp. 145-172. (21) Appl. No.: 09/373,211 Yilgör et al., “Polysiloxane Containing Copolymers: A Sur vey of Recent Developments.” Advances in Polymer Sci (22) Filed: Aug. 12, 1999 ence, 86, 1 (1988). Yu et al., “Anionic polymerization and copolymerization of Related U.S. Application Data cyclosiloxanes initiated by trimethylsilylmethyllithium”, (62) Division of application No. 09/082,072, filed on May 20, Polymer Bulletin, 32, 35-40 (1994). 1998, now Pat. No. 6,031,060. Frye et al., “Reactions of Organolithium Reagents with (60) Provisional application No. 60/047,435, filed on May 22, Siloxane Substrates.” The Journal of Organic Chemistry, 1997.
    [Show full text]